National Geographic in the Womb (Not in English but still very educational)
Puppy Development From Birth to TWO YEARS OLD
Dogs are considered puppies from birth to one year of age and go through several puppy stages and development periods. A newborn puppy doesn't look much like a dog and goes through different stages of puppy development during his first twelve weeks. However, each dog develops differently, with smaller dogs tending to mature earlier and some large breeds not physically mature before they are two years old.
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Rate of puppy development also varies from breed to breed. For instance, Cocker Spaniel puppies open their eyes sooner than Fox Terrier puppies, and Basenji puppies develop teeth earlier than Shetland Sheepdog puppies. However, no matter the breed, all puppies are born totally dependent on the momma dog, technically called the bitch.
Newborns At birth, puppies are blind, deaf and toothless, unable to regulate body temperature, or even urinate or defecate on their own. Puppies depend on their mother and littermates for warmth, huddling in cozy piles to conserve body temperature. A puppy separated from this warm furry nest can quickly die from hypothermia—low body temperature. Cold, lonely puppies cry loudly to alert Mom to their predicament.
Puppies first experience the sensation of being petted when washed by their mother's stroking tongue. The bitch licks her babies all over to keep them and the nest clean, and also to stimulate them to defecate and urinate.
Newborn puppies vary in size depending on the breed; tiny dogs, like the Chihuahua, produce puppies about four inches long, while giant breed newborns, like Great Dane puppies, may be twice that size.
Neonatal Period: Birth to Two Weeks For the first two weeks of life, puppies sleep nearly 90 percent of the time, spending their awake time nursing.
All their energy is funneled into growing, and birth weight doubles the first week.
Newborns aren't able to support their weight and crawl about with paddling motions of their front legs. The limited locomotion provides the exercise that develops muscles and coordination, and soon the puppies are crawling over and around each other and their mother.
From birth, puppies are able to use their sense of smell and touch, which helps them root about the nest to find their mother's scent-marked breasts. The first milk the mother produces is called colostrum. It is rich in antibodies that provide passive immunity and help protect the babies from disease during these early weeks of life.
Transitional Period: Week Two-to-Four The second week of life brings great changes for the puppy. Ears and eyes sealed since birth begin to open during this period, ears at about two weeks and eyelids between ten to 16 days. This gives the furry babies a new sense of their world. They learn what their mother and other dogs look and sound like, and begin to expand their own vocabulary from grunts and mews to yelps, whines, and barks.
Puppies generally stand by day 15 and take their first wobbly walk by day 21.
By age three weeks, puppy development advances from the neonatal period to the transitional period. This is a time of rapid physical and sensory development, during which the puppies go from total dependence on Mom to a bit of independence. They begin to play with their littermates, learn about their environment and canine society, and begin sampling food from Mom's bowl. Puppy teeth begin to erupt until all the baby teeth are in by about five to six weeks of age. Puppies can control their need to potty by this age, and begin moving away from sleeping quarters to eliminate.
Socialization Period: Week Four-to-Twelve Following the transitional phase, puppies enter the socialization period at the end of the third week of life; it lasts until about week ten. It is during this socialization period that interaction with others increases, and puppies form attachments they will remember the rest of their life.
Beginning at four weeks of age, mom's milk production begins to slow down just as the puppies' energy needs increase. As the mother dog slowly weans her babies from nursing, they begin sampling solid food in earnest.
The most critical period--age six to eight weeks--is when puppies most easily learn to accept others as a part of their family. The environmental stimulation impacts your puppy's rate of mental development during this time. The puppy brain waves look that of an adult dog by about the 50th day, but he's not yet programmed--that's your job and the job of his mom and siblings. Weaning typically is complete by week eight.
Week Eight-to-Twelve Puppies often go through a "fear period" during this time. Instead of meeting new or familiar people and objects with curiosity, they react with fearfulness. Anything that frightens them at this age may have a lasting impact so take care that the baby isn't overstimulated with too many changes or challenges at one time. That doesn't mean your pup will grow up to be a scaredy-cat; it's simply a normal part of development where pups learn to be more cautious. Careful socialization during this period helps counter fear reactions.
Puppies may be placed in new homes once they are eating well on their own. However, they will be better adjusted and make better pets by staying and interacting with littermates and the Mom until they are at least eight weeks old--older generally is better. Interacting with siblings and Mom help teach bite inhibition, how to understand and react to normal canine communication, and their place in doggy society. Puppies tend to make transitions from one environment to another more easily at this age, too.
Your puppy still has lots of growing to do. He won't be considered an adult until he goes through several more developmental periods and reaches one to two years of age.
Even though he may look grown up, the stages of puppy development last from birth to a year or even two before he's considered an adult dog. The greatest puppy development changes happen from birth to twelve weeks of age. But from twelve weeks on, your fur-kid still has lots of growing up to do.
Juvenile Period The juvenile puppy period generally begins at age ten weeks and lasts until puberty and the onset of sexual maturity. It is during this period that puppies begin to learn the consequences of behavior and determine what is most appropriate to certain circumstances.
Puppies at this age have boundless curiosity, exasperating stubbornness, and enthusiastic affection. Expect your puppy to get into everything, and you won't be disappointed. This is an ideal time to begin training.
10-16 Weeks: Juvenile Delinquent Pups Puppies test their boundaries during this period that lasts anywhere from a few days to several weeks. These dogs challenge owners to see who calls the shots, seem to “forget” any training they’ve learned, and act like rebellious teenagers.
Some of this has to do with teething. Pups lose baby teeth starting about three months of age. There can be discomfort as the permanent teeth erupt and puppies tend to chew more on anything and everything to relieve the pain.
Delinquent behavior also may be influenced by hormones. Unlike many other species, a male puppy’s testosterone level from age four-to-ten months may be up to five times higher than an adult dog’s. That’s so the adult canines recognize he’s a juvenile and needs “schooling” in the ways of dogs -- they make sure to knock him down a peg and teach manners before he gets too big for his furry britches.
But even pups that have been spayed and neutered prior to this can develop the “oh yeah, MAKE me!” attitude. Owners who have done everything right may still experience this difficult, frustrating phase. Grit your teeth, keep him on leash and under control, offer consistent, patient and humane training, and tell yourself, “He’s testing me, it’ll get better.” Because it will.
Four to Six Months Pups grow so quickly during this period you may notice changes every single day. Not only may your pup test and challenge you, this is the time frame puppies also figure out where they stand with other pets in the group.
Some squabbling and play fighting is expected. It’s a dog rule that older animals teach the pup limits, which is normal and usually sounds scarier than it is.
In fact, an un-neutered male puppy's testosterone level increases at around 4 to 5 months of age. This is one way adult dogs recognize that even big puppies are still babies and they must be taught proper dog etiquette.
Puppies can also sometimes experience another fear phase during this period. It may last up to a month, and there may be more than one especially in large breed dogs. This is normal and nothing to worry about. It tends to correspond with growth spurts, and you may notice some “flaky” behavior or unwarranted aggression, become protective of toys or territory. Just ensure you don’t reward the fearful behavior with more attention, and know how to talk to puppies and not use baby talk. It’s best to ignore the fear rather than risk rewarding it. Build confidence through training and the pup should transition out of it with no further problems.
Adolescence: Six to Twelve Months Most of your pup’s growth in height finishes by this period but he may continue to fill out and gain muscle mass and body weight. Puppy coat starts to be replaced by the adult coat.
While the baby may still be emotionally immature, during this period the boy pups begin to leg-lift and mark with urine. The testosterone level in male puppies increases to 5-7 times higher than in an adult dog by age 10 months, and then gradually falls to a normal adult level by about 18 months of age. This helps signal the senior male dogs that the youngster must be put in his place so you may notice more adult-pup squabbles during this period. Girl pups may go into heat (estrus) as early as five to six months, and boys begin to be interested in sex during this period.
Puppies at this age seem to explode with high energy and will do well with structured play and exercise. Training and continued socialization is vital to ensure your youngster knows how to behave politely with other dogs, other animals like cats, and other people including children and strangers of all sizes, ages, and looks.
Social Maturity: Between One and Two Years Depending on the breed, your dog will be physically mature at this age. Small dogsmature much earlier and larger ones take more time. Your pup’s social maturity also can depend on his or her experience with other animals. Socialization and training continue throughout your pet’s lifetime because there are always new things to learn -- or old lessons to revisit and practice. After all, the joy of your puppy’s first year or two predicts a lifetime of love to come.